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27

The simplex calling frequencies (146.520/446.000 Mhz) are intended for FM simplex communication, while the other pair (144.200/432.100) are for SSB. In general use, the term "simplex" implies FM modulation since FM is commonly used in both simplex and duplex operation. SSB, CW, and other modes are generally used for longer distance, simplex-only ...


11

In the absence of common-mode currents, then the optimum feedline length is 0, because a longer feedline only increases your feedline losses. These losses are due to the resistance of the wire, dielectric losses, etc. and are specified in dB per unit length in the coax datasheet. At VHF and up, these losses can be significant even at car lengths, especially ...


9

As one solution, you can combine the antennas with a power divider. See How to combine two 50 Ω antennas such that they appear as one 50 Ω load? This makes your pair of antennas into a phased array. If there's no overlap between their coverage, you effectively lose half your antenna gain, or 3 dB. This is because on transmit, half your power goes into the ...


8

Assuming that both antennas are 50 Ω resistive, they will combine in parallel for a 25 Ω load impedance when transmitting. This will cause the transmitter to see a 2:1 SWR. This is a 0.333 voltage reflection coefficient so ~11% of the transmitter power will be returned to the transmitter from the tee junction. The remaining 89% of the power will be split ...


7

144.200/432.100 are intended for SSB Modulation. 146.520/446.000 are intended for FM Modulation.


7

If I connect two antennas to one radio using a t connector will it work? That depends on your t-connector. If your tee really is just a branch in the inner conductor and connected outer conducters, than the other two answers are correct: your input impedance will be different than your output impedance. If, however, the tee is meant to be used in a ...


6

The ARRL has addressed this in detail: Is It Legal? By Brennan Price, N4QX and ARRL General Counsel Chris Imlay, W3KD What Part 97 regulations govern VoIP-assisted Amateur Radio? All of them or none of them, depending on whether you're asking about the "VoIP-assisted" or the "Amateur Radio" part of VoIP-assisted Amateur Radio. Follow this ...


6

2m isn't a good band if you want to do anything digital. Digital modes just aren't very popular on 2m. I think the only digital activity you are likely to find is: D-STAR APRS D-STAR uses GMSK, but the data for voice transmitted on that channel relies on a proprietary codec called AMBE. Any software that can encode or decode it is almost surely illegal, ...


6

For receiving it should work up to a certain level. However, the impedance will be completely different from that of a single antenna. So the SWR will be too high for transmitting and reception will normally be less efficient than with a single antenna. The best way to use two different antennas is to use a coax switch.


5

146.520 MHz is the national calling frequency for FM voice. It's a "simplex" frequency, meaning that you call on this frequency and then listen for a reply on the same frequency. (It is "national" in the US, but that does not guarantee that many people are actively monitoring this frequency! YMMV) If you're interested in other modes, there are other more-...


4

n2yo.com is a wonderful resource for keeping track of all of the orbiting satellites. It has many resources for tracking info to enter into tracking software and other places. It also shows a live google map of the location of each satellite.: amsat.org also has a wealth of information about contacting and tracking the satellites including uplink and ...


4

At 8W, the power from the radio is 9.03dB. With the cable losses of the receiving station being 1.5dB (1.41W), and the antenna receiving 1.733e-8W, it appears the received signal will never make it to the receiving station's radio. This seems to be the crux of your misunderstanding. You can't convert watts into decibels, or decibels into watts. A ...


4

It is equally important to consider the pattern of the antenna. If you hang a 1/2 wave antenna vertically, there will be minimal radiation in the earth facing direction. This will be most problematic for HF NVIS contacts. You may also wish to check the RF resistance of 38 AWG wire on 2 meters. I roughly calculate it to be > 100 ohms at 146 MHz for 10 meters ...


4

History and tradition are good choices of words, yes. Historically, they have been the most popular bands for mobile work; the antennas are small enough for a vehicle and many repeaters have been constructed for that reason. 6 meters used to be a popular mobile band back in the 50s and 60s. (For that matter, so were 80 and even 160.) All those bands ...


4

Worthy of mention is that 432MHz is a harmonic of 144MHz, meaning that the antenna can be much simpler; if it's (electrically) an odd number of half-waves on 2m, it's also an odd number of half-waves on 432MHz.


4

As far as I know, none of that series "speaks" APRS by itself, so you'd need your external controller to generated the AFSK tones. Whilst it's possible to generate AFSK at such low rates with an arduino or the like – wouldn't a simple "proper" computer like a raspberry pi or so not be the better choice here? You could basically run any ham software for ...


3

From the symptoms you state of not being able to hear transmissions from identical setups only 4 miles from each other, and then being able to have one person receive with the rubber duck antenna, it tells me your J-Pole antennas are not behaving ideally on the frequency you choose. Consider that an antenna like a J-Pole has about a 10MHz bandwidth in the ...


3

Combining multiple power amplifiers is a standard technique for generating high power from a number of lower-power components. You feed all amplifiers with the same input (split the input with transformers or other devices) and combine amplifiers through transformers. For example, 4 25 Watt amplifiers will give you an equivalent 100 Watt amplifier. (These ...


3

If you are worried about range the best thing you can do is get a full sized antenna that you can remotely mount, either on your backpack or elsewhere, and feed it with a short feed line (pigtail). The rubber ducky antennas that come with HT's are very lossy. There are several 2m/440 antennas that can break down with a small allen wrench, so that you could ...


3

You should have no problems doing 7 km with a (presumably 5W) HT even with the rubber duck antenna, outside. If you wanted to talk from inside, you will probably want an exterior antenna, but almost any common 2m antennas will do the job. A simple J pole is popular, you could even use a mobile antenna sited out a window.


3

Based on my somewhat short experience as a ham, these are some of the things I find very useful in my shack or would like to have: a comfy chair paper/writing instruments and/or computer for logging purposes a hook or clippy thing to hang your microphone from (if you're not using a desk or boom mic) shelves. you can never have enough shelves in the shack. a ...


3

For VHF, choice of polarization is not up to your desired radiation pattern, but who you want to be able to communicate with. In HF, the ionosphere causes random rotation of your signal's polarization, but in all line-of-sight communication, VHF or higher, there is no such rotation and a polarization mismatch can result in no signal at all. You should use ...


3

According to Alan McLean of Industry Canada if a radio approved for use in LMR service in Canada, for example, can be software reprogrammed (without hardware modifications) to be used on the amateur bands, then such reprogramming and use is permitted by any Canada amateur radio license class as it is considered an SDR under section 44: In regard to the ...


3

When dealing with UHF and VHF communications, height is often the determining factor of range for line of sight conditions. If there are obstructions that height cannot overcome, then more effective radiated power tends to be the determining factor. Exact placement on the roof won't have much effect on the pattern. If you place it way to one side of the ...


3

Reaching a repeater 30 miles (48 km) away with a mountain in between, with a handheld, sounds nearly impossible. Reaching a repeater 15 miles away with a ridge in the way with a handheld sounds very difficult. You could experiment with several improvements: A better omnidirectional antenna up high, like on the roof A radio with more power, like a 50 W ...


2

Let's assume that this antenna you describe, when operated at 145 MHz, has an SWR of 1:1, and behaves like an ideal antenna. At 145 MHz, the 1/4 wave vertical, plus the image antenna formed by the ground plane, make it effectively like a 1/2 wave dipole. It will have a free-space radiation pattern like this, for an antenna oriented vertically along the Z-...


2

Trouble shooting equipment such as an antenna analyzer and VOM, replacement parts (PL-259's, etc), a soldering iron. Provisions for expansion as needed (another operator at your station during a disaster, etc.) Your initial list is a great start but it assumes nothing is going to go wrong.


2

Will getting the antenna higher and in the clear improve things? Probably. How much? Something between "some" and "not at all". It depends on what's in your pack and the very specific geometry involved. The easiest way to quantify the change is to try it and see. Is it worth doing, given the necessary work, and the inconvenience of having an antenna ...


2

It's just the default setting. You can change it either through the menus or with the software, depending on which model radio you have.


2

You'll have to be more specific about what “the primary” is (give your radio model and the exact words/labels it uses in your question) for a more definite answer, but most likely it's simply that 144.000 MHz is the lowest frequency that is part of the 2-meter band (this is true worldwide), so it's a reasonable place to start for a VFO which has got to have ...


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